EXPLORATION OF ELECTROLYTES FOR ZN-ANODE RECHARGEABLE BATTERIES: ROOM TEMPERATURE IONIC LIQUIDS AS MAJOR OR SUPPORTING COMPONENTS

摘要

For Zn-anode rechargeable batteries, there are a number of shortcomings associated with using traditional KOH aqueous electrolytes. These include drying-out of the electrolyte due to water evaporation and dendrite formation at the anode, which severely impair battery performance (e.g., cycle life and capacity) and limit their application. It is, therefore, critical to either modify conventional KOH aqueous electrolytes or explore alternative electrolytes to eliminate these bottlenecks to the development of a feasible Zn-anode rechargeable battery system. Room temperature ionic liquids (RTILs) in recent years have been increasingly recognized as potential electrolytes or electrolyte components for rechargeable batteries. Compared with alkaline electrolytes, a simple electrolyte system composed of an RTIL as the sole component faces the challenge of improving its low conductivity before it can be practically applied in a battery. In this chapter, water and/or dimethyl sulfoxide modified RTILs (composed of pyrrolidinium or imidazolium cations and bis(trifluoromethanesulfonyl)imide or dicyanamide anions), with improved conductivity and Zn redox kinetics, are investigated as potential electrolyte systems for Zn-anode rechargeable batteries. In addition, with the capability of modifying metal deposit morphology, RTILs are found to be beneficial for depressing Zn dendrite formation in KOH aqueous electrolytes. An electrolyte, composed of 9M KOH + 5 wt% ZnO with a hydrophilic RTIL (0.5 wt% 1-ethyl-3-methylimidazolium dicyanamide), appears to be a promising electrolyte system for Zn-anode rechargeable batteries.